Method and apparatus for displaying overlapping markers

ABSTRACT

A computer implemented method, apparatus, and computer usable code for rendering graphical markers in a manner that avoids overlap of graphical markers on a map display. The process identifies a plurality of points for display from data describing locations and associated data about locations. The process determines whether displaying graphical markers for a set of points in the plurality of points will result in graphical markers overlapping each other. If the process determines that displaying graphical markers for the set of points will result in graphical markers overlapping each other, the process displays the graphical markers for the set of points in an arrangement that avoids overlap. Each graphical marker representing a point in the set of points does not overlap with any other marker associated with the map display when displayed in the arrangement that avoids overlap.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an improved data processingsystem and in particular to a method and apparatus for displaying maps.Still more particularly, the present invention relates to a computerimplemented method, apparatus, and computer usable program product foroptimizing the placement of overlapping markers in a mappingapplication.

2. Description of the Related Art

Currently, many applications use geospatial data to enhance the userexperience. Geospatial data is information that is both geographic andspatial pertaining to a location of natural or constructed features,objects, and/or structures. For example, latitude and longitudecoordinates are a type of geospatial data. Geospatial data can be usedto enhance application functions. Many data providers are now taggingdata with latitude and longitude coordinates.

In addition, the advent of mapping applications that are freelyavailable to users, such as Google® maps, enable users to easilyintegrate geospatial data into a map display. For example, the Chicagopolice now plot the occurrence of crimes by the type of crime andgeographic location of crimes across Chicago neighborhoods. As anotherexample, Google® mapping functions permit users to obtain drivingdirections using maps.

When geospatial data is integrated into a map display, each locationpoint associated with geospatial data is typically represented as agraphical marker, icon, or indicator on a map display. When large datasets representing a plurality of points are mapped, the markers mayoverlap. This overlap can occur where two or more points actually havethe same location. In addition, overlap can also occurs where pointshave different locations but graphical markers representing the pointsoverlap due to the zoom level of the map view. For example, where twopoints are located in different locations but in close proximity to eachother, the graphical markers for the two points may overlap in azoomed-in view, but appear as distinct, non-overlapping markers when themap is viewed in a zoomed-out view.

The overlapping of graphical markers representing points and/orlocations on a map results in problems because the overlap hides orobscures some of the data such that a user cannot clearly view eachpoint and/or location indicator. This overlap can cause confusion to auser attempting to locate a marker that is hidden or obscured by anothermarker.

SUMMARY OF THE INVENTION

The different illustrative embodiments provide a computer implementedmethod, apparatus, and computer usable program product for renderinggraphical markers in a manner that avoids overlap of graphical markerson a map display. The process identifies a plurality of points fordisplay from data describing locations and associated data aboutlocations. The process determines whether displaying graphical markersfor a set of points in the plurality of points will result in graphicalmarkers overlapping each other. If the process determines thatdisplaying graphical markers for the set of points will result ingraphical markers overlapping each other, the process displays thegraphical markers for the set of points in an arrangement that avoidsoverlap. Each graphical marker representing a point in the set of pointsdoes not overlap with any other marker associated with the map displaywhen displayed in the arrangement that avoids overlap.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbest be understood by reference to the following detailed description ofan illustrative embodiment when read in conjunction with theaccompanying drawings, wherein:

FIG. 1 is a pictorial representation of a network of data processingsystems in which illustrative embodiments may be implemented;

FIG. 2 is a block diagram of a data processing system in whichillustrative embodiments may be implemented;

FIG. 3A is a block diagram of a map display showing a currently useddisplay of overlapping graphical markers;

FIG. 3B is a block diagram of a map display showing another currentlyused display of overlapping graphical markers at a different zoom level;

FIG. 3C is another block diagram of a map display showing a currentlyused display of overlapping graphical markers with a diminishing overlapof graphical markers at a different zoom level;

FIG. 4 is a block diagram of a map display showing two sets of graphicalmarkers displayed in a non-overlapping, fan-shaped arrangement inaccordance with an illustrative embodiment;

FIG. 5 is a block diagram illustrating a dataflow when the processidentifies a set of overlapping graphical markers for display inassociation with a given map display using a fanned technique inaccordance with an illustrative embodiment;

FIG. 6 is a flowchart illustrating a process for displaying a set ofoverlapping graphical markers in a non-overlapping arrangement by usinga fanned technique in accordance with an illustrative embodiment;

FIG. 7 is an example of an algorithm for converting geospatial dataassociated with a data set to pixel values to form a set of plottedpoints; and

FIG. 8 is overlap-detection function for identifying a pair ofoverlapping graphical markers in accordance with an illustrativeembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference now to the figures and in particular with reference toFIGS. 1-2, exemplary diagrams of data processing environments areprovided in which illustrative embodiments may be implemented. It shouldbe appreciated that FIGS. 1-2 are only exemplary and are not intended toassert or imply any limitation with regard to the environments in whichdifferent embodiments may be implemented. Many modifications to thedepicted environments may be made.

With reference now to the figures, FIG. 1 depicts a pictorialrepresentation of a network of data processing systems in whichillustrative embodiments may be implemented. Network data processingsystem 100 is a network of computers in which embodiments may beimplemented. Network data processing system 100 contains network 102,which is the medium used to provide communications links between variousdevices and computers connected together within network data processingsystem 100. Network 102 may include connections, such as wire, wirelesscommunication links, or fiber optic cables.

In the depicted example, server 104 and server 106 connect to network102 along with storage unit 108. In addition, clients 110, 112, and 114connect to network 102. These clients 110, 112, and 114 may be, forexample, personal computers or network computers. In the depictedexample, server 104 provides data, such as boot files, operating systemimages, and applications to clients 110, 112, and 114. Clients 110, 112,and 114 are clients to server 104 in this example. Network dataprocessing system 100 may include additional servers, clients, and otherdevices not shown.

In the depicted example, network data processing system 100 is theInternet with network 102 representing a worldwide collection ofnetworks and gateways that use the Transmission ControlProtocol/Internet Protocol (TCP/IP) suite of protocols to communicatewith one another. At the heart of the Internet is a backbone ofhigh-speed data communication lines between major nodes or hostcomputers, consisting of thousands of commercial, governmental,educational and other computer systems that route data and messages. Ofcourse, network data processing system 100 also may be implemented as anumber of different types of networks, such as for example, an intranet,a local area network (LAN), or a wide area network (WAN). FIG. 1 isintended as an example, and not as an architectural limitation fordifferent embodiments.

With reference now to FIG. 2, a block diagram of a data processingsystem is shown in which illustrative embodiments may be implemented.Data processing system 200 is an example of a computer, such as server104 or client 110 in FIG. 1, in which computer usable code orinstructions implementing the processes may be located for theillustrative embodiments.

In the depicted example, data processing system 200 employs a hubarchitecture including a north bridge and memory controller hub (MCH)202 and a south bridge and input/output (I/O) controller hub (ICH) 204.Processor 206, main memory 208, and graphics processor 210 are coupledto north bridge and memory controller hub 202. Graphics processor 210may be coupled to the MCH through an accelerated graphics port (AGP),for example.

In the depicted example, local area network (LAN) adapter 212 is coupledto south bridge and I/O controller hub 204 and audio adapter 216,keyboard and mouse adapter 220, modem 222, read only memory (ROM) 224,universal serial bus (USB) ports and other communications ports 232, andPCI/PCIe devices 234 are coupled to south bridge and I/O controller hub204 through bus 238, and hard disk drive (HDD) 226 and CD-ROM drive 230are coupled to south bridge and I/O controller hub 204 through bus 240.PCI/PCIe devices may include, for example, Ethernet adapters, add-incards, and PC cards for notebook computers. PCI uses a card buscontroller, while PCIe does not. ROM 224 may be, for example, a flashbinary input/output system (BIOS). Hard disk drive 226 and CD-ROM drive230 may use, for example, an integrated drive electronics (IDE) orserial advanced technology attachment (SATA) interface. A super I/O(SIO) device 236 may be coupled to south bridge and I/O controller hub204.

An operating system runs on processor 206 and coordinates and providescontrol of various components within data processing system 200 in FIG.2. The operating system may be a commercially available operating systemsuch as Microsoft® Windows® XP (Microsoft and Windows are trademarks ofMicrosoft Corporation in the United States, other countries, or both).An object oriented programming system, such as the Java™ programmingsystem, may run in conjunction with the operating system and providescalls to the operating system from Java programs or applicationsexecuting on data processing system 200 (Java and all Java-basedtrademarks are trademarks of Sun Microsystems, Inc. in the UnitedStates, other countries, or both).

Instructions for the operating system, the object-oriented programmingsystem, and applications or programs are located on storage devices,such as hard disk drive 226, and may be loaded into main memory 208 forexecution by processor 206. The processes of the illustrativeembodiments may be performed by processor 206 using computer implementedinstructions, which may be located in a memory such as, for example,main memory 208, read only memory 224, or in one or more peripheraldevices.

The hardware in FIGS. 1-2 may vary depending on the implementation.Other internal hardware or peripheral devices, such as flash memory,equivalent non-volatile memory, or optical disk drives and the like, maybe used in addition to or in place of the hardware depicted in FIGS.1-2. Also, the processes of the illustrative embodiments may be appliedto a multiprocessor data processing system.

In some illustrative examples, data processing system 200 may be apersonal digital assistant (PDA), which is generally configured withflash memory to provide non-volatile memory for storing operating systemfiles and/or user-generated data. A bus system may be comprised of oneor more buses, such as a system bus, an I/O bus and a PCI bus. Of coursethe bus system may be implemented using any type of communicationsfabric or architecture that provides for a transfer of data betweendifferent components or devices attached to the fabric or architecture.A communications unit may include one or more devices used to transmitand receive data, such as a modem or a network adapter. A memory may be,for example, main memory 208 or a cache such as found in north bridgeand memory controller hub 202. A processing unit may include one or moreprocessors or CPUs. The depicted examples in FIGS. 1-2 andabove-described examples are not meant to imply architecturallimitations. For example, data processing system 200 also may be atablet computer, laptop computer, or telephone device in addition totaking the form of a PDA.

Today, many data providers are tagging their data with geospatial data.Geospatial data is information pertaining to a geographic location ofnatural or constructed features, structures, and/or objects. Geospatialdata includes data that is both geographic and spatial. For example,latitude and longitude coordinates are a type of geospatial data.Mapping applications, such as Google® maps, enable users to integrategeospatial data into a map display to represent information, such as aset of locations or addresses, as one or more graphical markers renderedin association with the map display.

As used herein, a point is a place, position, or locality. Each mappedpoint is represented on a map display by a graphical marker. As usedherein, a graphical marker is a visual indicator rendered on a mapdisplay to represent a point on a map display. This point in theseillustrative examples is relative to a map display bounding box and/orone or more other points associated with the map display. A graphicalmarker may take various forms, for example, an, image, icon, figure,character, symbol, letter, number, thumbnail image, or word. In theseexamples, a bounding box is the smallest upright rectangle, whichentirely encloses a figure on a display, such as a map display. Thus, inthis example, a map display bounding box is the smallest uprightrectangle which entirely encloses the map display. A graphic iconbounding box is the smallest upright rectangle which entirely enclosesthe graphical marker.

When large data sets representing a plurality of points are rendered ona map display, the graphical markers associated with the plurality ofpoints rendered on the map may overlap where the points are located atthe same coordinates as one or more other mapped points or in closeproximity to one or more other mapped points. The degree of overlap thatoccurs between a given pair of graphical markers is influenced by thezoom level of a map display view. Thus, two graphical markers mayoverlap in a zoomed-in view, but appear as distinct, non-overlappingmarkers when the map is viewed in a zoomed-out view.

For example, if a user conducts a search to find a list of availablejobs within a particular geographical area, the search will return aresult data set. In this example, the returned result data set includesa list of available jobs and/or locations, such as the following:

A Boat Operator B Store Human Resources Manager-Harahan, LA C RetailSales Consultant, Harahan D Applications Controls Engineer E WebsphereAdministrator F Mine Maintenance Mechanic G Industrial Hygienist HOracle 11i Financials (Technical)

With this example, each available job is associated with an alphabetletter identifier. The identifiers range from A to H, inclusive. Eachavailable job location can be rendered on a map display as a graphicalmarker labeled with the appropriate identifier associated with the givenavailable job. The set of graphical markers associated with the resultset of available jobs are rendered on a map display to represent thelocation of each available job in a result data set.

Referring now to FIG. 3A, which is a block diagram of a map displayhaving overlapping graphical markers, when the result data set ofavailable jobs is rendered as a plurality of graphical markers on a mapdisplay, some of the graphical markers overlap. Map display 300 is anytype of graphic map display generated by a mapping application, such asGoogle® maps. Map display 300 is rendered in association with aplurality of points represented on map display 300 as a plurality ofgraphical markers 310-340.

For example, as shown in FIG. 3A, graphical markers for pointsrepresented by graphic marker G 310, graphic marker F 320, graphicmarker E 330, and graphic marker H 340 are visible on the map display.However, graphic marker A, graphic marker B, graphic marker C, andgraphic marker D are hidden or obscured by other graphic markers, suchas graphic marker F 320, graphic marker E 330, and graphic marker H 340,due to overlap of the markers at the given zoom level for the map viewshown in FIG. 3A. As used herein, the term overlap refers to theobscuring or hiding of a portion of a graphical marker or all of agraphical marker by one or more other graphical markers rendered on thesame display. Thus, a graphical marker may overlap with only one othergraphical marker, such as in a single layer overlap, or a graphicalmarker may be overlapped by multiple other graphical markers, such as amultiple layer or stacked overlap.

Referring now to FIG. 3B, which is a block diagram of a map display withoverlapping graphical markers at a different zoom level in accordancewith an illustrative example, as a user zooms-in on the map displayview, the overlap of the graphical markers is diminished. Map display300 is any type of graphical map display generated by a mappingapplication, such as Google® maps. Graphic marker D 350, which wascompletely hidden or obscured at the zoom level shown in FIG. 3A ispartially visible at the zoom-in view of map display shown in FIG. 3B.

The term “zoom-in” refers to decreasing the field of vision/display bychanging the view from wide to narrower. Zooming-in typically increasesthe amount of detail over a narrower or smaller area of a map or image,such as the effect of increasing a magnification level. The term“zoom-out” refers to increasing the field of vision by changing the viewfrom narrow to a wider view. Zooming-out typically displays a larger orwider area but with a decreased amount of detail over that area, such asthe effect of decreasing a magnification level. Generally, mappingfunctions provide multiple levels of zoom-in and zoom-out. A zoom levelrefers to the particular level of zoom-in or zoom-out option enabled bya user in regard to a particular map display.

In addition, a graphical marker may be overlapped by another graphicalmarker in whole or in part. In accordance with one illustrative example,a graphical marker is overlapped by another graphical marker if anidentifier associated with the graphical marker is overlapped, hidden,or obscured by another graphical marker. In this illustrative example,graphic marker D 350 is partially hidden or overlapped by graphic markerE 330. However, because graphical marker D 350 has an identifier “D”that is not blocked, hidden, or otherwise obscured by graphic marker E330, graphic marker E 330 does not overlap with graphic marker D 350. Inother words, graphic marker E 330 does not overlap with graphic marker D350 because an identifier “D” associated with graphic marker D 350 isnot obscured by the other given graphical marker on the map display.However, in accordance with this example, graphic marker E 330 andgraphic marker D 350 could be overlapping or hiding one or more othergraphical markers that are not visible in this zoom level.

FIG. 3C is another block diagram of a map display showing a diminishingoverlap of graphical markers at a different zoom level in accordancewith an illustrative embodiment. Map display 300 is any type of graphicmap display generated by a mapping application, such as Google® maps.

In this illustrative example, a user has zoomed-in to increase amagnification level of the map display. Graphic marker D 350, which wascompletely obscured in FIG. 3A and partially obscured in FIG. 3B, iscompletely visible to a user at the zoom-in level of the map displayshown in FIG. 3C. In addition, graphic marker A 360, which was obscuredin FIGS. 3A and 3B, is partially visible at the zoom-in levelillustrated in FIG. 3C. Thus, as a user zooms-in, such as to increasethe magnification level of the map display, the overlap of graphicalmarkers may be diminished. However, even at the zoomed-in view shown inFIG. 3C, graphic marker B and graphic marker C are still not visible toa user. The overlapping of graphical markers obscures mapped points suchthat a user cannot clearly view each mapped point. This obscuring ofmapped points and data related to mapped points can additionally lead touser confusion.

Therefore, the different illustrative embodiments provide a computerimplemented method, apparatus, and computer usable code for optimizingplacement of overlapping graphical markers in a geographic mappingapplication using a fanned technique. The process converts geospatialdata associated with a data set to pixel values to form a plurality ofplotted points. The process identifies a set of graphical markers for aset of points that will overlap when displayed on the map display.

In response to identifying the set of overlapping graphical markers, theprocess displays the set of overlapping graphical markers for the set ofpoints in a manner that avoids overlap of the graphical markers for theset of points. In accordance with an illustrative embodiment, the set ofgraphical markers are displayed in a fan-shaped arrangement about acentral point associated with the set of overlapping graphical markersto avoid overlap of the graphical markers. Markers arranged in afan-shaped arrangement about a central point do not overlap with anyother graphical marker associated with the map display.

As used herein, a plotted point is a mapped point with pixel valuesrepresenting the location of the point relative to a particular mapdisplay and/or relative to one or more other points associated with themap display. An overlapping graphical marker is a graphical marker thatoverlaps, in whole or in part, with one or more other graphical markerswhen rendered on a particular map display at a given zoom level.Graphical markers for the plurality of plotted points are rendered on agiven map display in accordance with a pixel value for each plottedpoint. Thus, a graphical marker for a point can be an overlappinggraphical marker at one zoom level and a non-overlapping graphicalmarker at a different zoom level. As used herein, a non-overlappinggraphical marker is a graphical marker that does not hide or obscureanother graphical marker associated with a given map display. Inaccordance with another illustrative example, a non-overlappinggraphical marker is a graphical marker that does not hide or obscure anidentifier of another graphical marker associated with the map display.

The term “set of overlapping graphical markers” includes a single pairof overlapping graphical markers, as well as three or more overlappinggraphical markers. An overlapping graphical includes a graphical markerthat overlaps with a single other graphical marker, as well as agraphical marker that overlaps two or more other graphical markers.

FIG. 4 depicts a block diagram of a map display showing two sets ofgraphical markers displayed in a non-overlapping, fan-shaped arrangementin accordance with an illustrative embodiment. Map display 400 is anytype of graphical map display generated by a mapping application, suchas Google® maps. Map display 400 is rendered in association with aplurality of plotted points represented on map display 400 as aplurality of graphic markers 410-460.

Graphic marker F 410 is a single graphic marker representing a singlepoint. Graphic marker E 420 and graphic marker D 430 are displayed in afan-shaped arrangement on map display 400 to form set of graphic markers425. Set of graphic markers 425 comprises a single pair of graphicmarkers, graphic marker E 420 and graphic marker D 430. Set of graphicmarkers 425 represents a first identified set of overlapping graphicmarkers for a set of points identified from the plurality of pointsassociated with map display 400.

Set of graphic markers 425 is displayed in a non-overlapping, fan-shapedarrangement at a central point associated with the set of overlappinggraphical markers. Graphic marker E 420 and graphic marker D 430 do notoverlap with any other graphical markers in the plurality of graphicalmarkers associated with map display 400 because graphic marker E 420 andgraphic marker D 430 are displayed in a fan-shaped manner such that eachgraphical marker is clearly visible and un-obscured by any othergraphical when rendered on map display 400. In other words, graphicmarker E 420 and graphic marker D 430 are displayed in a fanned mannersuch that graphic marker E 420 and graphic marker D 430 do not overlapin the manner shown for graphic marker E 330 and graphic marker D 350 inFIGS. 3A and 3B.

Graphic marker H 440, graphic marker B 450 and graphic marker C 460 aredisplayed in a fan-shaped arrangement on map display 400 to form set offanned markers 465. Set of fanned markers 465 comprises three graphicmarkers, including graphic marker H 440, graphic marker B 450 andgraphic marker C 460. Set of fanned markers 465 represents a secondidentified set of overlapping graphic markers associated with mapdisplay 400. Set of fanned markers 465 is displayed in a fan-shapedarrangement about a central point associated with the set of overlappingmarkers. Each graphical marker included in set of fanned markers 465 isarranged in a fanned manner to avoid overlap of the graphical markers.

In this illustrative example, each graphical marker associated with setof fanned markers 425 is a wedge-shaped graphical marker representing adifferent plotted point in the identified set of points associated withset of fanned markers 425. However, in accordance with an illustrativeembodiment, each graphical marker associated with set of fanned markers425 may be rendered as a graphical marker having any shape that isarranged in a fanned or angled arrangement about a central point suchthat each graphical marker in the set of graphical markers does notoverlap with any other graphical marker associated with map display 400.

In this illustrative example, each graphical marker associated with setof fanned markers 425 and set of fanned markers 465 are displayed asgraphical markers having the same size and shape. In accordance withanother illustrative example, each graphical marker in set of fannedgraphic markers 425 and set of fanned markers 465 do not have the samesize and shape. For example, graphic marker H 440 and graphic marker C460 can be displayed as a short tear-drop shaped graphical marker whilegraphic marker B 450 is displayed as an elongated or long, thinstretched marker with a smaller width and greater height than graphicmarker H 440 and graphic marker C 460. In this manner, set of fannedmarkers 465 can accommodate a greater number of graphical markers in thefanned arrangement.

For example, if all graphical markers are rendered at the same pixelsize and shape, a set of fanned markers, such as set of fanned markers465, can only accommodate eight graphical markers arranged in a fannedmanner. However, when graphical markers are displayed in different pixelsize and a different shape of graphical marker, a greater number ofgraphical markers can be accommodated in a non-overlapping arrangement.For example, one or more graphical markers in an arrangement to avoidoverlap can be displayed in a stretched manner. A graphical markerdisplayed in a stretched manner has a smaller width and a greater heightthan a graphical marker displayed in a non-stretched manner. Thus, inthis example, when one or more graphical markers are displayed in astretched manner in a fan-shaped arrangement, the set of fanned markerscan accommodate a dozen graphical markers without resulting in anygraphical markers in the set of fanned markers overlapping with anyother graphical markers in the set of fanned markers. In accordance withthis illustrative embodiment, graphical markers in the set of fannedmarkers can be displayed as markers having varying dimensions, such aswidth and height, in order to permit a varying number of graphicalmarkers to be displayed in a single set of fanned markers.

In the illustrative embodiment shown in FIG. 4, each graphical marker ina set of fanned markers is displayed as an inverted tear-drop shapedgraphical indicator. However, in accordance with the illustrativeembodiments, a graphical marker displayed in a fanned shaped arrangementto form a set of fanned markers can be displayed in any shape, size,design, format, image, symbol, or any other graphic or image to indicatea point or location on a map display. In addition, a graphical markercan be displayed as a graphic having any color, border, and/or shadingin association with the graphical marker. For example, a graphicalmarker can be displayed as a long, thin graphic, a balloon-shapedgraphic in which a round or oval graphic is displayed at the end of aline or stem, a triangle or pie-slice shaped graphic, or any other sizeor shape of graphic that can be arranged in a fan-shaped manner about acentral point to avoid overlap of each graphical marker.

In order to determine if a graphical marker is an overlapping graphicalmarker at a given zoom level, information describing locations andassociated data about locations is identified. This geospatial datadescribing locations and data about locations is converted to aplurality of plotted points. The process determines a physical distancerepresented between pixels for a given zoom level of a map display. Thephysical distance represented can vary from one zoom level to anotherzoom level for a given map display. Geospatial data is converted to aplurality of plotted points based on the physical distance betweenpixels. The pixel value associated with a particular plotted pointidentifies a location on the map display for the point relative to abounding box for the map display. Each plotted point is represented as agraphical marker on a given map display.

The illustrative embodiments provide a computer implemented method,apparatus, and computer usable code for rendering graphic markers on amap display to avoid overlapping graphical markers by using a fannedtechnique to arrange the graphical markers on the map display. Theprocess converts geospatial data associated with a data set to pixelvalues to form a set of plotted points. In response to identifying agiven set of points associated with overlapping graphical markers, theprocess displays a set of overlapping graphical markers in anarrangement that avoids overlap of the graphical markers. In thisillustrative example, the process displays the overlapping graphicalmarkers in a fan-shaped arrangement to prevent overlap of the markers.In a fan-shaped arrangement, a set of graphical markers are displayed ina fanned manner about a central point to form a set of fanned markers.Graphical markers in the set of fanned markers are non-overlappingmarkers. In other words, the graphical markers arranged in a fan-shapedarrangement about a central point do not overlap any other markerassociated with the map display.

In accordance with another illustrative embodiment, a set of overlappinggraphical markers are displayed in a hub and spoke manner to preventoverlap of the graphical markers. In a hub and spoke manner, eachgraphical marker is displayed as a spoke branching off a central pointto form a circular pattern. In other words, each graphical markerattaches to a central point in a circular pattern, like a spoke in awheel. The hub and spokes arrangement about a central point forms acircle or wheel shaped set of graphical markers. Each graphical markerdisplayed in a hub and spokes manner does not overlap with any othergraphical marker in arranged in the hub and spokes manner.

FIG. 5 is a block diagram illustrating a dataflow when the processidentifies a set of overlapping graphical markers for display inassociation with a given map display using a fanned technique inaccordance with an illustrative embodiment. Computer 500 is any type ofcomputing device, such as a personal computer, laptop, personal digitalassistant, or any other computing device depicted in FIGS. 1 and 2. Mapmarker overlap engine 510 is a mapping application. Map marker overlapengine 510 converts geospatial data associated with a data set intopixel values associated with a given map display to form a plurality ofplotted points. Map marker overlap engine 510 identifies set(s) ofoverlapping graphical markers. Map marker overlap engine displays theset(s) of overlapping graphical markers as a set of graphical markersarranged in a manner that prevents overlap of the graphical markers. Inthis illustrative example, map marker overlap engine arranges the set ofoverlapping graphical markers in a fanned arrangement about a centralpoint associated with the given set of overlapping graphical markers.

Map marker overlap engine 510 receives the data set and associatedgeospatial data as a data set, such as data set 520. Data set 520includes data describing locations and associated data about locations.

Data set 520 can be received from a plurality of different sources. Inaccordance with this illustrative example, user 530 provides data set520 to map marker overlap engine 510 via user interface 540. Userinterface 540 is any type of known or available interface for providinginput to computer 500, including but not limited to, a graphical userinterface (GUI), a menu-driven interface, and/or a command lineinterface.

Map marker overlap engine 510 can also retrieve and/or receive data set520 from a local database located on computer 500, such as database 545.Database 545 is a database for storing information, such as locations,addresses, or any other data in conjunction with geospatial dataassociated with the stored information. Database 545 is located on orlocally to computer 500.

In addition, map marker overlap engine 510 also receives data set(s),such as data set 520, from a remote database, such as remote database550. Remote database 550 is any type of database for storing acollection of data that is not located on computer 500. In thisillustrative example, remote database 550 is located on server 560.

Server 560 is any type of server, such as server 104 and 106 in FIG. 1.Server 560 can be a server on a network, such as network 102 describedin FIG. 1. Computer 500 accesses remote database 550 on server 560through a network connection via network device 570.

Network device 570 is any type of network access software known oravailable for allowing computer 500 to access a network. Network device570 connects to a network connection, such as network 102 in FIG. 1. Thenetwork connection permits access to any type of network, such as alocal area network (LAN), a wide area network (WAN), or the Internet.

Map marker overlap engine 510 receives data set 520. Map marker overlapengine 510 utilizes geospatial data in data set 520 to determine a pixelvalue for a plurality of points to be displayed in association with agiven map display. Map marker overlap engine 510 converts geospatialdata into pixel values for the given map display by determining thephysical distance that is represented between pixels associated with thegiven map display. Map marker overlap engine 510 then converts thegeospatial data for each point or location in data set 520 into a pixellocation to form a plotted point. This geospatial data may be forexample latitude and longitude coordinates.

Map marker overlap engine 510 determines whether displaying graphicalmarkers for a set of points in the plurality of plotted points willresult in overlapping graphical markers. Map marker overlap engine 510utilizes a known pixel size for a graphical marker to identify one ormore set(s) of points that will result in overlap of graphical markers.A set of overlapping graphical markers comprises at least one graphicalmarker that will wholly or partially overlap one or more other graphicalmarkers when the graphical is rendered in association with the mapdisplay in accordance with a pixel value for each point and a pixel sizefor each graphical marker. In other words, map marker overlap engine 510determines a position for each graphical marker relative to a boundingbox for a given map display and/or relative to every other graphicalmarker to be displayed and identifies graphical markers that will occupythe same pixel locations causing graphical marker overlap when renderedon a given map display.

Map marker overlap engine 510 optimizes the display of overlappingmarkers by rendering overlapping markers in an arrangement that preventoverlap. For example, overlapping markers are rendered in a fannedmanner such that none of the rendered graphical markers overlap anyother rendered graphical marker. In other words, the pixels occupied byeach graphical marker do not occupy the same pixel position as anothergraphical marker so that no graphical marker is obscured or hiddenbehind another rendered graphical marker.

In order to convert geospatial data into pixel values for a given mapdisplay, map marker overlap engine 510 determines the dimensions of abounding box for the given map display in pixels. Map marker overlapengine 510 determines the geographic coordinates, such as latitude andlongitude, for each point in data set 520. Map marker overlap engine 510establishes the pixel location for each point in the plurality of pointsrepresented by information in data set 520 rather than a latitude andlongitude location in order to determine whether points will overlapwhen displayed on the given map display. In other words, visual overlapcannot be determined based on geographic coordinates alone except wheregeographic coordinates are identical due to differences in themagnification level of different zoom levels for a map display.

Map marker overlap engine plots the set of overlapping graphical markersfor display in a fanned manner by calculating a central point orcentroid of a bounding polygon associated with the set of fannedmarkers. In this example, a bounding polygon is the smallest polygonshaped box enclosing the known pixel size for the set of fanned markers.Each graphical marker representing a plotted point in the set of fannedmarkers is rendered as a wedge-shaped graphical marker positioned at thecentral point of the bounding polygon to form the set of fanned markers.

In accordance with an illustrative embodiment, each time a user changesa zoom level of a map display, the map marker overlap enginerecalculates a pixel value for each point and performs a new set ofoverlap detection functions for each pair of plotted points to identifyany sets of overlapping graphical markers.

In accordance with anther illustrative embodiment, each graphical markerin a fanned graphical marker is a wedge-shaped graphical marker of apredetermined pixel size. For example, each wedge in a fanned graphicalmarker can be one-eighth (⅛) the size of the fanned graphical marker. Insuch a case, the optimum number of plotted points is eight plottedpoints with identifiers that are clearly visible to a user. In otherwords, the fanned graphical marker can optimally represent a maximum ofeight graphical markers representing eight plotted points. In order torepresent additional plotted points in excess of the optimal number ofplotted points, a size of each wedge graphical marker in the fannedgraphical marker is adjusted to permit additional graphical markers tobe displayed as part of the fanned graphical marker. However, as thegraphical size of each wedge graphical marker is diminished, the detailvisible to a user is also diminished.

In accordance with another illustrative embodiment, in order torepresent additional plotted points in excess of the optimal number ofplotted points a second display page is linked to the fanned graphicalmarker. The second display page includes a result set listing eachplotted point represented by the wedge graphical markers comprising thefanned graphical marker. When a user clicks on the fanned graphicalmarker or otherwise selects the fanned graphical, the result list in thesecond display is presented to the user detailing the list of pointsrepresented by the fanned graphical marker.

In another illustrative embodiment, a set if fanned markers is linked toa second display. The second display presents at least a portion of theassociated data about locations for the plurality of points representedby the graphical markers arranged in the fan-shaped manner. In otherwords, a user can obtain additional information regarding each pointrepresented by a graphical indicator in the set of fanned markers byselecting to view a second display screen providing a listing of dataregarding the point and/or location represented by the selectedgraphical marker. In this example, a user can select a graphical markerin the set of fanned markers by clicking on the graphical marker.

In accordance with another illustrative embodiment, a user can click onthe fanned graphical marker to select a fanned out display option. Afanned out display option changes a zoom level of the given map displayto the appropriate magnification or zoom level at which each graphicalmarker in the set of overlapping graphical markers is no longeroverlapping with any other graphical marker. In other words, as a userzooms in on a map display, the magnification level increases and thedegree of overlap of graphical markers decreases. In accordance withthis illustrative embodiment, if a user clicks on a set of fannedgraphical markers representing a set of points, the map marker overlapengine automatically changes the zoom level of the map display to thesecond zoom level at which each graphical marker in the set of fannedgraphical markers is non-overlapping graphical marker. At this secondzoom level, the graphical markers for the set of points do not need tobe displayed in a fanned arrangement to avoid overlap of the graphicalmarkers because at this second zoom level the graphical markers aresufficiently spaced apart so that overlap of the markers no longeroccurs.

In accordance with another illustrative embodiment, each graphicalmarker is configurable. A configurable graphical marker can beconfigured by a user to indicate that a given graphical marker is anoverlapping marker by changing a color of the graphical marker, changinga shape of the graphical marker, changing a border or outline of thegraphical marker, adding a shading or shadow to the graphical marker orany combination of changes to the graphical marker to indicate that thegraphical marker is overlapping, hiding or obscuring one or more othergraphical markers. A configurable graphical marker is a user configuredgraphical marker. In accordance with another illustrative embodiment, aconfigurable graphical marker is a pre-configured graphical marker withone or more default configurations that may be modified or altered by auser.

In accordance with another illustrative embodiment, an overlap detectiondetermination is made based on a distance of a plotted point from afixed reference point. A fixed reference point may be any pointdesignated as a fixed reference point, including but not limited to, acenter of a city, a body of water, a state, a country, a continent,and/or any other natural or artificial geographic location or point ofinterest.

FIG. 6 is a flowchart illustrating a process for displaying a set ofoverlapping graphical markers in a non-overlapping arrangement by usinga fanned technique in accordance with an illustrative embodiment. Theprocess is performed by a mapping application, such as map markeroverlap engine 510 in FIG. 5.

The process begins by determining a zoom level for a given map display(step 610). The process next determines pixel values for each point inthe set of points with associated geospatial data obtained from a dataset (step 620) to from a plurality of plotted points. The processidentified a given unprocessed point (step 630) in the plurality ofpoints. As used herein, an unprocessed point is a point that has notbeen processed to determine if the point overlaps with any other pointin the plurality of plotted points.

The process determines if a graphical marker for the given plotted pointoverlaps with any other graphical marker (step 640). If the givengraphical marker does overlap with any other graphical marker, theprocess flags the pair of points (step 650) represented by the pair ofoverlapping graphical markers. If the process determines that thegraphical marker does not overlap with any other graphical marker, theprocess determines if any other plotted points in the set of plottedpoints are unprocessed (step 660). If any plotted points are unprocessedpoints, the process returns to step 630 and continues to perform steps630-660 iteratively until all plotted points are processed to determineif a graphical marker for each point overlaps with any other graphicalmarker. The process then displays the identified set of overlappingmarkers using a fanned technique (step 670).

The process determines if the zoom level of the given map display hasbeen changed (step 680). If the zoom level has been changed, the processreturns to step 620. If the process determines that a zoom level has notbeen changed, the process terminates thereafter.

FIG. 7 is an example of an algorithm for converting geospatial dataassociated with a data set to pixel values to form a set of plottedpoints. The code shown in FIG. 7 is implemented by a mappingapplication, such as map marker overlap engine 510 in FIG. 5.

Code 710 is an algorithm for a function to convert latitude andlongitude coordinates of the map bounding box into a pixel value for thehorizontal x-axis 620 and a pixel value for the vertical y-axis 730 ofeach point relative to the bounding box for the map display to form theset of plotted points.

The map marker overlap engine determines whether or not a graphicalmarker for each point in a pair of plotted points overlaps. Thisdetermination is made for every plotted point by comparing a pixel valuefor each plotted point and a known graphical marker pixel size with apixel value for every other plotted point in the plurality of plottedpoints. Thus, an overlap determination is made for each pair ofgraphical markers representing each pair of plotted points for a totalof N² comparisons, where N is the total number of plotted points in theplurality of plotted points. In accordance with an illustrativeembodiment, the total number of comparisons is optimized such that thetotal number of comparisons is less than N² comparisons.

FIG. 8 is overlap-detection function for identifying a pair ofoverlapping graphical markers in accordance with an illustrativeembodiment. The code shown in FIG. 8 is implemented by a mappingapplication, such as map marker overlap engine 510 in FIG. 5.

Code 800 is a pseudocode for an overlap-detection function to determineif a graphical marker for a first plotted point overlaps with agraphical marker for a second plotted point. Each plotted point has anassociated graphical marker of a known size. A comparison is made of theknown dimensions of the bounding box of a graphical marker to determineif the graphical marker overlaps with the second graphical marker. Inaccordance with pseudocode 810, if either a left bound or a right boundof a bounding box associated with the first graphical marker, identifiedas graphical marker A, falls between a left and right bounds of thebounding box for the second graphical marker, identified as graphicalmarker B and either a top bound or a bottom bound of the first graphicalmarker falls between an upper and lower bound of the bounding boxassociated with the second graphical marker, then the two plotted pointsare identified as overlapping at line of code 820. If the bounding boxesassociated with the two graphical markers do not overlap, then the twoplotted points represented by the two graphical markers are notidentified as a pair of overlapping graphical markers.

Thus, in accordance with this illustrative embodiment, the map markeroverlap engine compares the known dimensions of the bounding boxesassociated with two graphical markers representing two plotted points todetermine if the bounding boxes overlap. If the bounding boxes overlapin whole or in part, then map marker overlap engine flags the pair ofplotted points as points having overlapping graphical markers. The pairof overlapping graphical markers form a set of overlapping graphicalmarkers. A set of overlapping graphical markers can include two or moreoverlapping graphical markers. Each graphical marker in the set ofoverlapping graphical markers overlaps with at least one other graphicalmarker in the set of overlapping graphical markers. As used herein, agraphical marker that overlaps with another graphical marker includes agraphical marker that hides or obscures another graphical marker, inaddition to a graphical marker that is itself hidden or obscured byanother graphical marker. For example, a set of overlapping markers caninclude a single graphical marker that hides or obscures two othergraphical markers in a stacked manner. In such a case, all threemarkers, the top marker, the middle marker, and the bottom marker, areoverlapping graphical markers.

Map marker overlap engine determines whether each pair of graphicalmarkers representing a pair of plotted points in the plurality ofplotted points are overlapping graphical markers. In accordance withthis illustrative example, approximately N² overlap detectiondeterminations are made. For example, if the plurality of plotted pointsincludes only four points, then sixteen (16) overlap determinations aremade. In accordance with another illustrative embodiment, the number ofoverlap determinations can be optimized. Thus, if there are four plottedpoints in the plurality of plotted points, A, B, C, and D, then mapmarker overlap engine performs an overlap detection determination as toeach of the following pairs of points: A and B, A and C, A and D, B andA, B and C, B and D, C and A, C and B, C and A, D and A, D and B, and Dand C. Therefore, a minimum of twelve (12) overlap-detectiondeterminations are made rather than sixteen (16).

After comparing all points in the plurality of plotted points, mapmarker overlap engine determines which plotted points are represented byoverlapping graphical markers. Map marker overlap engine identifiesset(s) of overlapping graphical markers. Each set of overlapping markersis plotted for display in an arrangement that prevents overlap ofgraphical markers. For example, an arrangement that prevents overlap ofgraphical markers includes a fanned manner. In a fanned arrangement,each graphical marker is displayed in a fan-shaped set of graphicalmarkers in which each graphical marker does not overlap with any othergraphical marker. The set of graphical markers displayed in a fannedmanner forms a set of fanned markers. In accordance with an illustrativeembodiment, the set of fanned markers is a pre-generated image.

When large data sets representing a plurality of points are mapped, thegraphical markers may overlap when displayed on a map display. Overlapof markers can occur when two or more points actually have the samelocation. Overlap can also occur when two or more graphical markersoverlap due to the zoom level of the map view. Overlapping of graphicalmarkers on a map results in problems because the overlap hides orobscures some of the data intended to be represented on the map display.This obscuring of data can cause confusion to a user.

Thus, the aspects of the illustrative embodiments provide a method,apparatus, and computer program product for rendering graphical markersin a manner that avoids overlap of graphical markers on a map display.Graphical markers that would overlap when displayed in a given zoomlevel are arranged using a fanned technique. By displaying graphicalmarkers for a set of points in a fanned manner, the identifier for eachgraphical marker is clearly visible and/or un-obscured by any othergraphical marker for a set of points. Thus, a user is able to identifyeach location and/or point represented by a graphical marker on the mapdisplay. In this way, data represented by graphical markers is not lost,hidden, or obscured by overlapping markers.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems which perform the specified functions or acts, or combinationsof special purpose hardware and computer instructions.

The invention can take the form of an entirely hardware embodiment, anentirely software embodiment or an embodiment containing both hardwareand software elements. In a preferred embodiment, the invention isimplemented in software, which includes but is not limited to firmware,resident software, microcode, etc.

Furthermore, the invention can take the form of a computer programproduct accessible from a computer-usable or computer-readable mediumproviding program code for use by or in connection with a computer orany instruction execution system. For the purposes of this description,a computer-usable or computer readable medium can be any tangibleapparatus that can contain, store, communicate, propagate, or transportthe program for use by or in connection with the instruction executionsystem, apparatus, or device.

The medium can be an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system (or apparatus or device) or apropagation medium. Examples of a computer-readable medium include asemiconductor or solid state memory, magnetic tape, a removable computerdiskette, a random access memory (RAM), a read-only memory (ROM), arigid magnetic disk and an optical disk. Current examples of opticaldisks include compact disk-read only memory (CD-ROM), compactdisk-read/write (CD-R/W) and DVD.

A data processing system suitable for storing and/or executing programcode will include at least one processor coupled directly or indirectlyto memory elements through a system bus. The memory elements can includelocal memory employed during actual execution of the program code, bulkstorage, and cache memories which provide temporary storage of at leastsome program code in order to reduce the number of times code must beretrieved from bulk storage during execution.

Input/output or I/O devices (including but not limited to keyboards,displays, pointing devices, etc.) can be coupled to the system eitherdirectly or through intervening I/O controllers.

Network adapters may also be coupled to the system to enable the dataprocessing system to become coupled to other data processing systems orremote printers or storage devices through intervening private or publicnetworks. Modems, cable modem and Ethernet cards are just a few of thecurrently available types of network adapters.

The description of the present invention has been presented for purposesof illustration and description, and is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the art. Theembodiment was chosen and described in order to best explain theprinciples of the invention, the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

1. A computer implemented method for rendering graphical markers in amanner that avoids overlap of graphical markers on a map display, thecomputer implemented method comprising; identifying a plurality ofpoints for display from data describing locations and associated dataabout locations; determining whether displaying graphical markers for aset of points in the plurality of points will result in graphicalmarkers overlapping each other; and responsive to a determination thatdisplaying graphical markers for the set of points will result ingraphical markers overlapping each other, displaying the graphicalmarkers for the set of points in an arrangement that avoids overlap,wherein each graphical marker representing a point in the set of pointsdoes not overlap with any other graphical marker associated with the mapdisplay when displayed in the arrangement that avoids overlap, furthercomprising: displaying the graphical markers in a fan-shaped arrangementto form a set of fanned markers, wherein each graphical marker in theset of fanned graphical markers does not overlap with any othergraphical marker.
 2. The computer implemented method of claim 1 furthercomprising: determining whether a given pair of graphical markersassociated with a pair of points overlap based on a distance of aphysical distance between pixels associated with the pair of pointsrelative to a bounding box of the map display.
 3. The computerimplemented method of claim 1 further comprising: determining whether agiven pair of graphical markers associated with a pair of points overlapbased on a distance between the pair of points and a fixed referencepoint.
 4. The computer implemented method of claim 1 further comprising:determining if a graphical marker for a given plotted point in theplurality of plotted points overlaps with any other graphical markerassociated with the map display.
 5. The computer implemented method ofclaim 1 further comprising: determining a zoom level for the mapdisplay.
 6. The computer implemented method of claim 1 whereingeospatial data comprises longitude and latitude coordinates for a givenpoint.
 7. The computer implemented method of claim 1 wherein the set offanned markers is a pre-generated graphical image.
 8. The computerimplemented method of claim 1 further comprising: displaying the set offanned markers at a central point associated with the graphical markersfor the set of points.
 9. The computer implemented method of claim 1further comprising: responsive to a user selecting the set of fannedmarkers, changing a first zoom level of the map display to a second zoomlevel, wherein each graphical marker for the set of points will notoverlap with any other graphical marker for the set of points when thegraphical markers are not displayed in a fan-shaped arrangement at thesecond zoom level.
 10. The computer implemented method of claim 1wherein a graphical marker is a user configurable graphical marker. 11.The computer implemented method of claim 1 wherein a graphical markerdoes not overlap with any other marker associated with the map displayif an identifier associated with the graphical marker is not obscured byany other graphical marker associated with the map display.